Quattro generations (was: Miata Torsen)

[Ti Kan]

RyanWeath at aol.com writes:
> Ti, Thank you for clarifying. . I knew there was a veyr high chance I
> wouldn't be exactly correct. .question though, on older audis 4k, 5k,
> CQ, etc, where the front and rear diff arent EDL, what are they??

There are several generations of Audi quattro:
(US models and years, Euro model year vary)

1. circa 1982-88 "quattro I"
   - Front open diff
   - Center open diff with vacuum operated manual lock
   - Rear open diff with vacuum operated manual lock

   This system is not ABS-friendly because locking the diffs effectively
   eliminates any speed difference between wheels, disabling ABS wheel
   speed sensor function.  On the 5K/100/200 models that has ABS, it is
   automatically disabled when a diff lock is activated.
   Used on 1982-85 UrQ, 84-87 4Kq, 86-88 5Kq/100q/200q

2. circa 1988-95 "quattro II"
   - Front open diff
   - Center Torsen diff
   - Rear open diff with vacuum operated manual lock

   The rear diff lock will auto-disengage at >15mph, so the system is
   ABS-compatible.
   Used on 1988-94 80q/90q/CoupeQ, 100q/200q

3. circa 1990-94 "quattro III"
   - Front open diff
   - Center planetary gear with electronically controlled multi-plate clutch
   - Rear Torsen diff

   Used on the V8q with auto-trans only.  The 1991 V8q with manual trans
   has a center Torsen diff.

4. circa 1996-present "quattro IV"
   - Front open diff with EDL
   - Center Torsen diff
   - Rear open diff with EDL

   Used on 1996-current A4q/S4, A6q/allroad, 1997-current A8/S8

5. circa 2000-present "no official quattro generation designation"
   - Front open diff with EDL
   - Center Haldex
   - Rear open diff with EDL

   This system is used, probably mostly due to the fact that the "standard"
   quattro layout doesn't fit the transversely mounted engine configuration
   of the TT and the A3/S3.  This system, unlike the others is primarily FWD,
   until slip is detected on the front and then torque is directed to the
   rear.
   Used on 2000-current TTq

-Ti
01 S4 2.7 biturbo quattro
84 5000S 2.1 turbo
80 4000 2.0
96 A4 2.8 quattro (sold but not forgotten)
-- 
    ///  Ti Kan                Vorsprung durch Technik
   ///   AMB Research Laboratories, Sunnyvale, CA. USA
  ///    ti at amb.org
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